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Abstract:

Disclosed are processes for the production of fluorinated olefins,
preferably adapted to commercialization of CF3CF═CH2
(1234yf). In certain preferred embodiments the processes comprise first
exposing a compound of Formula (IA)
C(X)2═CClC(X)3 (IA)
where each X is independently F, Cl or H, preferably
CCl2═CClCH2Cl, to one or more sets of reaction conditions,
but preferably a substantially single set of reaction conditions,
effective to produce at least one chlorofluoropropane, preferably in
accordance with Formula (IB):
CF3CClX'C(X')3 Formula (IB)
where each X' is independently F, Cl or H, and then exposing the compound
of Formula (IB) to one or more sets of reaction conditions, but
preferably a substantially single set of reaction conditions, effective
to produce a compound of Formula (II)
CF3CF═CHZ (II)
where Z is H, F, Cl, I or Br.

Claims:

1.-10. (canceled)

11. A method for producing fluorinated organic compounds comprising: (a)
reacting in a liquid phase in the presence of at least a first catalyst a
compound of Formula (IA): C(X).sub.2.dbd.CClC(X)3 (IA) where each
X is independently H or Cl, to produce at least one compound of Formula
(IB): CF3CClX'C(X')3 Formula (IB) where each X' is
independently F, Cl or H; and (b) reacting said compound of Formula (IB)
under conditions effective to produce a compound of Formula (II):
CF3CF═CHZ (II) where each Z is H or Cl.

12. The method of claim 11 wherein said compound of Formula IA is a
tetrachloropropene.

13. The method of claim 12 wherein said tetrachloropropene is selected
from the group consisting of CCl2H--CCl═CClH and
CCl3--CCl═CH.sub.2.

15. A method for producing fluorinated organic compounds comprising: (a)
reacting in a liquid phase, in the presence of at least a first catalyst,
and at a temperature of about 30.degree. C. to about 200.degree. C., a
compound of Formula (I): C(X)mCCl(Y)nC(X)m (I) where
each X is independently H, F, Cl, I or Br, and each m is independently 2
or 3, and n is 0 or 1, to produce at least one compound of Formula (IB):
CF3CClX'C(X')3 Formula (IB) where each X' is independently F,
Cl or H.

16. The method of claim 15 wherein m is 3 and n is 1.

17. The method of claim 16 wherein X is H or Cl.

18. The method of claim 15 wherein the compound of Formula (I) is at
least one of CCl3--CClH--CClH2, CCl2H--CCl═CClH, and
CCl3--CCl═CH.sub.2.

19. The method of claim 15 further comprising (b) reacting said compound
of Formula (IB) under conditions effective to produce a compound of
Formula (II): CF3CF═CHZ (II) where each Z is H or Cl.

20. The method of claim 19 wherein the compound of Formula II is
2,3,3,3-tetrafluoro-1-propene (HFO-1234yf).

Description:

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application is a Divisional of U.S. application Ser. No.
12/185,042, filed on Aug. 1, 2008 (now pending), which claims priority
benefit of U.S. Provisional Application No. 60/953,528, filed on Aug. 2,
2007, which in turn is also a Continuation-In-Part of U.S. application
Ser. No. 11/619,592, filed Jan. 3, 2007 (now pending) which claims
priority benefit of U.S. Provisional Application No. 60/755,485, filed
Jan. 3, 2006. each of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] (1) Field of Invention

[0003] This invention relates to novel methods for preparing fluorinated
organic compounds, and more particularly to methods of producing
fluorinated olefins having a fluorine on an unsaturated non-terminal
carbon.

[0006] Several methods of preparing hydrofluoroalkenes are known. For
example, U.S. Pat. No. 4,900,874 (Ihara, et. al) describes a method of
making fluorine containing olefins by contacting hydrogen gas with
fluorinated alcohols. Although this appears to be a relatively high-yield
process, commercial handling of hydrogen gas at high temperature is
generally unsafe. Also, the cost of producing hydrogen gas, such as
building an on-site hydrogen plant, can be, in many situations,
prohibitive.

[0007] U.S. Pat. No. 2,931,840 (Marquis) describes a method of making
fluorine containing olefins by pyrolysis of methyl chloride and
tetrafluoroethylene or chlorodifluoromethane. This process produces a
relatively low yield and a very large percentage of unwanted and/or
unimportant byproducts.

[0008] The preparation of HFO-1234yf from trifluoroacetylacetone and
sulfur tetrafluoride has been described. See Banks, et al., Journal of
Fluorine Chemistry, Vol. 82, Iss. 2, p. 171-174 (1997). Also, U.S. Pat.
No. 5,162,594 (Krespan) discloses a process wherein tetrafluoroethylene
is reacted with another fluorinated ethylene in the liquid phase to
produce a polyfluoroolefin product.

SUMMARY OF INVENTION

[0009] One aspect of the invention involves methods of producing
hydrofluoroalkenes, more preferably fluorinated olefins having a fluorine
on an unsaturated non-terminal carbon and even more preferably in certain
preferred embodiments 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf). In
preferred forms, this aspect of the invention is directed to methods
comprising converting at least one compound of Formula (I):

C(X)mCCl(Y)nC(X)m (I)

to at least one compound of Formula (II)

CF3CF═CHZ (II)

where each X, Y and Z is independently H, F, Cl, I or Br, and each m is
independently 1, 2 or 3, preferably 2 or 3, and n is 0 or 1. In certain
preferred embodiments, compounds of Formula I include
CH2═CClCCl3, CCl2═CClCH2Cl, and
1,1,1,2,3-pentachloropropane. As used herein and throughout, unless
specifically indicated otherwise, the term "converting" includes directly
converting (for example, in a single reaction or under essentially one
set of reaction conditions) and indirectly converting (for example,
through two or more reactions or using more than a single set of reaction
conditions).

[0010] In certain preferred embodiments of the invention, the compound of
Formula (I) comprises a compound wherein n is 0, each X is independently
H or Cl, and Z is H. Such preferred embodiments include converting at
least one C3 alkene in accordance with Formula (IA):

C(X)2═CClC(X)3 (IA)

to at least one compound of formula (II)

CF3CF═CHZ (II)

where each X is independently H or Cl. Preferably the one or more
compounds of Formula (IA) are tetrachloropropene(s), and are even more
preferably selected from the group consisting of
CH2═CClCCl3, CCl2═CClCH2Cl, and combinations
of these. In certain highly preferred embodiments, the at least one C3
alkene in accordance with Formula (IA) comprises, and preferably
comprises in a major proportion based on all compounds of Formula (I),
CCl2═CClCH2Cl.

[0011] In certain preferred embodiments the converting step comprises
first exposing the compound of Formula (I), and preferably Formula (IA),
and even more preferably CCl2═CClCH2Cl, to one or more sets
of reaction conditions, but preferably a substantially single set of
reaction conditions, effective to produce at least one
chlorofluoropropane, more preferably a propane in accordance with Formula
(IB):

CF3CClXC(X)3 Formula (IB)

where each X is independently F, Cl or H, preferably where one X is F and
the remaining X's are H, and then exposing the compound of Formula (IB)
to one or more sets of reaction conditions, but preferably a
substantially single set of reaction conditions, effective to produce a
compound of Formula (II), most preferably HFO-1234yf. In certain
preferred embodiments, at least one of said X in Formula (IB) is Cl. In
such embodiments, it is generally preferred that X on the non-terminal
carbon is H, and even more preferably that in addition that at least two,
and more preferably all three X on the terminal carbon are also H.

[0012] As used herein, the term "substantially single set of reaction
conditions" means that the reaction is controlled to correspond to be
within a set of reaction parameters that would ordinarily be considered
to be a single stage or unit operation. As those skilled in the art will
appreciate, such conditions permit a degree of design variability within
each of the process parameters relevant to the conversion step.

[0013] The preferred conversion step of the present invention is
preferably carried out under conditions, including the use of one or more
reactions, effective to provide an overall Formula (I) conversion of at
least about 50%, more preferably at least about 75%, and even more
preferably at least about 90%. In certain preferred embodiments the
overall conversion of Formula (I) is at least about 95%, and more
preferably at least about 97%. Further, in certain preferred embodiments,
the step of converting the compound of Formula (I) to produce a compound
of Formula (II) is conducted under conditions effective to provide an
overall Formula (II) yield of at least about 75%, more preferably at
least about 85%, and more preferably at least about 90%. In certain
preferred embodiments an overall yield of about 95% or greater is
achieved.

[0014] In the preferred embodiments in which the conversion step comprises
exposing a compound of Formula (I), and even more preferably
CCl2═CClCH2Cl, to one or more sets of reaction conditions
effective to produce at least one chlorofluoropropane, more preferably a
propane in accordance with Formula (IB), such an exposing step preferably
comprises exposing the compound of Formula (I) to one or more set of
reaction conditions, but preferably substantially a single set of
reaction conditions, effective to provide an overall conversion of
Formula (I), and preferably Formula (IA) of at least about 75%, and more
preferably at least about 90%, and more preferably at least about 97%,
such conditions also preferably being effective to provide a Formula (IB)
selectivity yield of at least about 10%, more preferably at least about
15%, and even more preferably at least about 20%.

[0015] One preferred aspect of the present invention provides a process
for the production of 2-chloro-1,1,1,2-tetrafluoropropane (HCFC244bb)
comprising reacting a compound selected from the group consisting of
1,1,2,3-tetrachloropropene, 1,1,1,2,3-pentachloropropane (HCC-240 db),
2,3,3,3-tetrachloropropene and combinations of these with a fluorinating
agent, preferably hydrogen fluoride, in a liquid phase reaction vessel in
the presence of a liquid phase fluorination catalyst.

[0016] Another preferred aspect of the invention provides a process for
the production of 2,3,3,3-tetrafluoropropene comprising (i) reacting,
preferably in a continuous process, at least one compound selected from
the group consisting of 1,1,2,3-tetrachloropropene,
1,1,1,2,3-pentachloropropane (HCC-240 db), and 2,3,3,3-tetrachloropropene
with a fluorinating agent, preferably hydrogen fluoride, in a liquid
phase reaction in the presence of a liquid phase fluorination catalyst to
produce a reaction product comprising 2-chloro-1,1,1,2-tetrafluoropropane
(HCFC-244bb); and then (ii) reacting, preferably by dehydrohalogenating,
the 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) under conditions
effective to produce 2,3,3,3-tetrafluoropropene.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a chart showing the yield of HFC-1234yf according to an
embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0018] One beneficial aspect of the present invention is that it enables
the production of desirable fluoroolefins, preferably C3 fluoroolefins,
using relatively high conversion reactions. Furthermore, the present
methods in certain preferred embodiments permit the production of the
desirable fluoroolefins, either directly or indirectly, from relatively
attractive starting materials. For example, tetrachloropropene, and
1,1,2,3 tetrachloropropene (CCl2═CClCH2Cl) in particular,
is a compound that in certain embodiments is an advantageous starting
material.

[0019] In certain preferred embodiments, at least a first compound in
accordance with Formula (I), and preferably a compound in accordance with
Formula (IA), is exposed to one or more reaction conditions effective to
produce a second compound in accordance with Formula (I), and preferably
a compound in accordance with Formula (IB), which in turn is exposed to
one or more reaction conditions effective to produce a reaction product
containing one or more of the desired fluoroolefins, preferably one or
more compounds of Formula (II), and even more preferably HFO-1234yf.
Thus, in preferred embodiments, the conversion step comprises a series of
at least two reaction stages or conditions. In one preferred aspect of
the present invention, the conversion step comprises: (a) reacting a
compound of Formula (IA), such as tetrachloropropene, preferably in a
liquid phase reaction in the presence of at least a first catalyst to
produce at least one compound of Formula (IB), such as a
monochloro-tetrafluoro-propane, preferably
2-chloro-1,1,1,2-tetrafluoropropane (HFC-244bb); and (b) reacting said
compound of Formula (IB), in a gas and/or liquid phase, to produce the
desired HFO, preferably HFO-1234yf.

[0020] In certain preferred embodiments, the present methods comprise
converting at least one tetrachloropropene and/or at least one
pentachloropropane to a reaction product containing the desired
tetrafluoropropene, preferably 2,3,3,3-tetrafluoropropene (HFO-1234yf).
Although it is contemplated that the converting step in certain
embodiments may effectively be carried out in a single reaction stage
and/or under a single set of reaction conditions, it is preferred in many
embodiments that the converting steps comprise a series of two reaction
stages or conditions. In one preferred aspect of the present invention,
the conversion step comprises: (a) reacting at least one
tetrachloropropene (preferably, 1,1,2,3-tetrachloropropene and/or
2,3,3,3-tetrachloropropene), or at least one pentachloropropane
(1,1,1,2,3-pentachloropropane) or mixtures of two or more thereof, in a
liquid and/or gas phase reaction in the presence of at least a first
catalyst to produce at least one C3 hydrochlorofluorocarbon such as a
mono-chloro-tetrafluoro-propane, preferably HCFC-244bb; and (b) reacting
said C3 hydrochlorofluorocarbon, such as a monochloro-tetrafluoropropane
compound, in a gas and/or liquid phase and preferably in the presence of
at least a catalyst, preferably a second catalyst which is different than
the first catalyst, to produce the desired tetrafluoropropene, preferably
HFO-1234yf.

[0021] Each of the preferred reaction steps is described in detail below,
with the headings being used for convenience but not necessarily by way
of limitation.

I. Fluorination of the Compound of Formula (IA)

[0022] One preferred reaction step in accordance with the present
invention may be described by those reactions in which the compound of
Formula (IA) is fluorinated to produce a compound of Formula (IB). In
certain preferred embodiments, especially embodiments in which the
compound of Formula (IA) comprises C(X)2═CClC(X)3, where
each X is independently H or Cl, the present converting step comprises
reacting said Formula (IA) compound(s) by fluorinating, preferably in a
liquid phase and with HF as a fluorinating agent, said compound(s) to
produce a compound of Formula (IB), namely,

CF3CClX'C(X')3 Formula (IB)

where each X' is independently F, Cl or H. The preferred fluorination of
the compound of Formula (IA) is preferably carried out under conditions
effective to provide a Formula (IA) conversion of at least about 50%,
more preferably at least about 75%, and even more preferably at least
about 90%. In certain preferred embodiments the conversion is at least
about 95%, and more preferably at least about 97%. Further, in certain
preferred embodiments, the conversion of the compound of Formula (IA)
comprises reacting such compound under conditions effective to produce at
least one compound of Formula (IB), such as monochlorotetrafluoropropane
(preferably HCFC-244bb) at a selectivity of at least about 10%, more
preferably at least about 15%, and more preferably at least about 20%.

[0023] In certain preferred embodiments in which the feed material
comprises tetrachloropropene, the present converting step is carried out
under conditions effective to provide a tetrachloropropene conversion of
at least about 40%, more preferably at least about 55%, and even more
preferably at least about 70%. In certain preferred embodiments the
conversion of tetrachloropropene is at least about 90%, and more
preferably about 100%. Further, in certain preferred embodiments, the
conversion of the tetrachloropropene to produce a C3
hydrochlorofluorocarbon is conducted under conditions effective to
provide a C3 hydrochlorofluorocarbon selectivity of at least about 85%,
more preferably at least about 90%, and more preferably at least about
95%, and even more preferably about 100%.

[0024] In a particularly preferred embodiment, the invention relates to a
continuous method for producing a compound of Formula (IB), preferably
including 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb), by either a
liquid phase fluorination, a vapor phase fluorination, or a combination
of liquid and vapor phase fluorinations. In certain preferred
embodiments, the feed to the fluorination reaction comprises at least one
chlorocarbon or mixed chlorocarbon feed material, preferably selected
from the group consisting of 1,1,1,2,3-pentachloropropane (HCC-240 db),
2,3,3,3-tetrachloropropene, and 1,1,2,3,-tetrachloropropene (HCC-1230xa.
The compounds in the feed are reacted with a fluorinating agent, such as
hydrogen fluoride, to produce a reaction product stream comprising a
compound according to Formula (IB), such as
2-chloro-1,1,1,2-tetrafluoropropane, hydrogen fluoride, and hydrogen
chloride.

[0025] In certain embodiments, it is preferred that the fluorination
reaction step is carried out in the liquid phase, and preferably under a
substantially single set of reaction conditions, and it is contemplated
that the reaction can be carried out batch wise, continuous, or a
combination of these, with continuous reaction being preferred. In a
preferred form of a continuous process, the Formula (I) compound, such as
1,1,2,3-tetrachloropropene, and the fluorinating agent, such as HF, are
preferably fed, preferably substantially simultaneously, to the reactor
after the reactor reaches the desired temperature. The temperature and
pressure of the fluorination reaction are generally within about the same
range for both the batch and continuous modes of operation.

[0026] For embodiments in which the reaction comprises a liquid phase
reaction, preferably a catalytic process is used. In general, it is
contemplated that any liquid phase fluorination catalyst may be used.
Lewis acid catalyst, metal-halide catalysts, including antimony halides,
tin halides, tantalum halides, titanium halides, transition
metal-halides, such as iron halides, niobium halide, and molybdenum
halide, transition metal oxides, Group IVb metal halides, a Group Vb
metal halides, fluorinated chrome halide, a fluorinated chrome oxide and
combinations of two or more of these, are preferred in certain
embodiments. Metal chlorides and metal fluorides are particularly
preferred. Examples of particularly preferred catalysts of this type
include SbCl5, SbCl3, SbF5, SnCl4, TaCl5,
NbCl5, MoCl6, TiCl4, FeCl3, a fluorinated species of
SbCl5, a fluorinated species of SbCl3, a fluorinated species of
SnCl4, a fluorinated species of TaCl5, a fluorinated species of
TiCl4, a fluorinated species of NbCl5, a fluorinated species of
MoCl6, a fluorinated species of FeCl3, and combinations of two
or more of these. Pentavalent metal halide, particularly pentavalent
antimony halides are preferred in many embodiments. Antimony chlorides,
such as antimony pentachloride, and/or fluorinated antimony chlorides are
preferred in many embodiments.

[0027] In certain preferred embodiments, a liquid phase catalyst as
described above is charged into a fluorination reactor prior to heating
the reactor. The catalyst may (or may not) be activated with anhydrous
hydrogen fluoride HF (hydrogen fluoride gas) and/or Cl2 (chlorine
gas) before use depending on the state of the catalyst.

[0028] In preferred liquid phase fluorination of Formula (I) compounds,
preferably Formula (IA) compounds, the reaction is at least partially a
catalyzed reaction, and is preferably carried out on a continuous basis
by introducing a stream containing the compound of Formula (I),
preferably Formula (IA), into one or more reaction vessels. The stream
containing the compound of Formula (I), and preferably Formula (IA),
which may be preheated if desired, is introduced into a reaction vessel,
which is maintained at the desired temperature, preferably from about
30° C. to about 200° C., more preferably from about
50° C. to about 150° C., more preferably from about
75° C. to about 125° C., even more preferably in certain
embodiments from about 90° C. to about 110° C., wherein it
is preferably contacted with catalyst and fluorinating agent, such as HF.

[0029] It is generally preferred that the fluorinating agent is present in
the reactor in substantial excess. For example, for embodiments in which
the fluorinating agent is HF, it is preferred that the reactor be fed
with HF in an amount to produce an HF:Formula (IB) ratio in the reactor
product stream (on a molar basis) of at least about 4:1, more preferably
from about 4:1 to about 50:1, more preferably from about 4:1 to about
30:1 and most preferably from about 5:1 to about 20:1.

[0030] With respect to the feeds to the reactor, including the
fluorination agent, it is generally considered that water will react with
and deactivate the catalyst. Therefore it is preferred that the feed be
substantially free of water. With respect to embodiments in which HF is
used as a fluorinating agent, substantially anhydrous HF is preferred. By
"substantially anhydrous" is meant that the HF contains less than about
0.05 weight % water and preferably contains less than about 0.02 weight %
water. However, one of ordinary skill in the art will appreciate that the
presence of water in the catalyst can be compensated for by increasing
the amount of catalyst used. HF suitable for use in the reaction may be
purchased from Honeywell International Inc. of Morristown, N.J.

[0031] Although it is contemplated that residence times in the reactor may
vary widely within the scope of the present invention, it is preferred in
certain embodiments that for continuous reactions the residence time is
relatively short. The residence time or contact time in certain preferred
embodiments is from about 1 second to about 2 hours, preferably from
about 5 seconds to about 1 hour and most preferably from about 10 seconds
to about 30 minutes. The quantity of catalyst is generally selected to
ensure that the desired level of fluorination is achieved in view of the
other process conditions which apply, such as the residence times
described above. For example, less than about 5 seconds, more preferably
less than about 3 seconds, and even more preferably about 2 seconds or
less.

[0032] Without necessarily being bound to any particular theory of
operation it is believed that the preferred fluorination reaction
proceedings in accordance with the following reaction equation:

CCl2═CClCH2Cl+4HF→CF3CClFCH3+3HCl

[0033] It is expected that by-products of the reaction will include
CF3CCl═CH2 (HFO-1233xf), CClF2CCl═CH2
(HFO-1232xf), and that one or both of these could be recycled, completely
or partially, to improve the overall yield of the desired
CF3CClFCH3 (HCFC-244bb).

[0034] In general, it is contemplated that any reactor suitable for a
fluorination reaction may be used in accordance with the preferred
aspects of the present invention. Preferably the vessel is comprised of
materials which are resistant to corrosion as Hastelloy, Inconel, Monel
and/or fluoropolymer-lined. Such liquid phase fluorination reactors are
well known in the art.

[0035] Preferably in certain embodiments, the vessel contains catalyst,
for example a fixed or fluid catalyst bed, packed with a suitable
fluorination catalyst, with suitable means to ensure that the reaction
mixture is maintained with the desired reaction temperature range.

[0036] In general it is also contemplated that a wide variety of reaction
pressures may be used for the fluorination reaction, depending again on
relevant factors such as the specific catalyst being used, the
temperature of the reaction, the amount of fluorinating agent being used,
and other factors. The reaction pressure can be, for example,
superatmospheric, atmospheric or under vacuum and in certain preferred
embodiments is from about 5 to about 200 psia, and in certain embodiments
from about 30 to about 175 psia and most preferably about 60 psia to
about 150 psia.

[0037] In certain embodiments, an inert diluent gas, such as nitrogen, may
be used in combination with the other reactor feed(s).

[0038] It is contemplated that the amount of catalyst used will vary
depending on the particular parameters present in each embodiment. In
certain preferred embodiments, the catalyst is present in an amount of
from about 2% to about 80%, and preferably from about 5% to about 50%,
and most preferably from about 10% to about 20%, based on the mole
percent of the desired reaction product, preferably a compound in
accordance with formula (IB), and even more preferably HCFC-244bb.
Fluorination catalysts having a purity of at least 98% are preferred.

[0039] The catalysts can be readily regenerated by any means known in the
art if they become deactivated. One suitable method of regenerating the
catalyst involves flowing a stream of chlorine through the catalyst. For
example, from about 0.002 to about 0.2 lb per hour of chlorine can be
added to the liquid phase reaction for every pound of liquid phase
fluorination catalyst. This may be done, for example, for from about 1 to
about 2 hours or continuously at a temperature of from about 65°
C. to about 100° C.

[0040] In another embodiment, the fluorination reaction is done in the
vapor-phase. In preferred aspects of the vapor phase reaction, the
fluorinating agent, such as HF (hydrogen fluoride gas) is fed
continuously through the catalyst bed. After a short time with
substantially only the HF feed stream, a compound according to Formula
(I), and preferably Formula IA, such as 1,1,2,3-tetrachloropropene, is
fed continuously through the catalyst bed at a fluorinating agent Formula
(I) mole ratio, preferably HF/1,1,2,3-tetrachloropropene mole ratio, of
about 4:1 to about 50:1 and preferably of about 4:1 to about 30:1 and
more preferably of about 5:1 to about 20:1. The reaction is preferably
carried out at a temperature of from about 30° C. to about
200° C. (preferably from about 50° C. to about 120°
C.) and at a pressure of about 5 psia to about 200 psia (pounds per
square inch absolute) (preferably from about 30 psia to about 175 psia).
The catalyst may be supported on a substrate, such as on activated
carbon, or may be unsupported or free-standing. It may be preferred in
certain embodiments to activate the catalyst, such as with anhydrous
hydrogen fluoride HF (hydrogen fluoride gas) and/or Cl2 (chlorine
gas) before use depending on the state of the catalyst. If desired, the
catalyst can be kept activated by the continuous or batch addition of
Cl2 or a similar oxidizing agent.

[0042] In general, the effluent from the fluorination reaction step,
including any intermediate effluents that may be present in multi-stage
reactor arrangements, may be processed to achieve desired degrees of
separation and/or other processing. For example, in embodiments in which
the reactor effluent comprises a compound of Formula (IB), such as
HCFC-244bb, the effluent will generally also include HF and HCl. Some
portion or substantially all of these components of the reaction product
may be recovered from the reaction mixture via any separation or
purification method known in the art such as neutralization and
distillation, or in the reaction product may be fed in its entirety or in
part, but without any separation of components, to the next step, i.e.,
dehydrohalogenation of the compound of Formula (IB). It is contemplated,
therefore, that the desired compound of Formula (IB), such as HCFC-244bb,
can be used in subpure form, or optionally in partially pure form or
impure form with at least a portion of the effluent from the HCFC-244bb
production step used as the feed to the dehydrohalogenation step.

[0043] In a continuous mode of operation, the desired compound(s) of
Formula (IB), such as HCFC-244bb, and other reaction products, such as
hydrogen chloride, are preferably continuously removed from the reactor.

II. Dehydrohalogenation of Formula (IB)

[0044] One preferred reaction step in accordance with the present
invention may be described by those reactions in which the compound of
Formula (IB) is dehydrohalogenated, preferably in certain embodiments
dehydrochlorinated, to produce a compound of Formula (II). In certain
preferred embodiments, the compound of Formula (IB) comprises a
monochloro-tetrafluoro-propane, more preferably,
2-chloro-1,1,1,2-tetrafluoropropane (HCFC244bb), which is exposed to
reaction conditions to produce a reaction product according to Formula
(II), preferably comprising tetrafluoropropene, preferably
2,3,3,3-tetrafluoropropene HFO-1234yf.

[0045] In certain preferred embodiments, the stream containing the
compound of Formula (IB) is preheated to a temperature of from about
150° C. to about 400° C., preferably about 350° C.,
and introduced into a reaction vessel, which is maintained at about the
desired temperature, preferably from about 200° C. to about
700° C., more preferably from about 300° C. to about
700° C., more preferably from about 300° C. to about
450° C., and more preferably in certain embodiments from about
350° C. to about 450° C.

[0046] Preferably the vessel is comprised of materials which are resistant
to corrosion as Hastelloy, Inconel, Monel and/or fluoropolymers linings.
Preferably the vessel contains catalyst, for example a fixed or fluid
catalyst bed, packed with a suitable dehydrohalogenation catalyst, with
suitable means to heat the reaction mixture to about the desired reaction
temperature.

[0047] Thus, it is contemplated that the dehydrohalogenation reaction step
may be performed using a wide variety of process parameters and process
conditions in view of the overall teachings contained herein. However, it
is preferred in certain embodiments that this reaction step comprises a
gas phase reaction, preferably in the presence of catalyst, and even more
preferably in the presence of a fixed bed catalytic reactor in the vapor
or gas phase.

[0048] In preferred embodiments, the catalyst is a carbon- and/or
metal-based catalyst, preferably activated carbon (in bulk or supported
form), a nickel-based catalyst (such as Ni-mesh), metal halides,
halogenated metal oxides, neutral (or zero oxidation state) metal or
metal alloy and combinations of these. Other catalysts and catalyst
supports may be used, including palladium on carbon, palladium-based
catalyst (including palladium on aluminum oxides), and it is expected
that many other catalysts may be used depending on the requirements of
particular embodiments in view of the teachings contained herein. When
metal halides or metal oxides catalysts are used, preferably mono-, bi-,
and tri-valent metal halides, oxide and their mixtures/combinations, and
more preferably mono-, and bi-valent metal halides and their
mixtures/combinations. Component metals include, but are not limited to,
Cr3+, Fe3+, Mg2+, Ca2+, Ni2+, Zn2+,
Pd2+, Li.sup.+, Na.sup.+, K.sup.+, and Cs.sup.+. Component halogens
include, but are not limited to, F.sup.-, Cl.sup.-, Br.sup.-, and
I.sup.-. Examples of useful mono- or bi-valent metal halide include, but
are not limited to, LiF, NaF, KF, CsF, MgF2, CaF2, LiCl, NaCl,
KCl, and CsCl. Halogenation treatments can include any of those known in
the prior art, particularly those that employ HF, F2, HCl, Cl2,
HBr, Br2, HI, and I2 as the halogenation source. When neutral,
i.e., zero valent, metals, metal alloys and their mixtures are used.
Useful metals include, but are not limited to, Pd, Pt, Rh, Fe, Co, Ni,
Cu, Mo, Cr, Mn, and combinations of the foregoing as alloys or mixtures.
The catalyst may be supported or unsupported. Useful examples of metal
alloys include, but are not limited to, SS 316, Monel 400, Inconel 825,
Inconel 600, and Inconel 625.

[0049] Of course, two or more any of these catalysts, or other catalysts
not named here, may be used in combination.

[0050] The gas phase dehydrohalogenation reaction may be conducted, for
example, by introducing a gaseous form of a compound of Formula (IB) into
a suitable reaction vessel or reactor. Preferably the vessel is comprised
of materials which are resistant to corrosion, especially to the
corrosive effects of hydrogen chloride (to the extent that such material
is formed under the dehydrohalogenation conditions) as mentioned above.
Preferably the vapor phase reaction vessel contains catalyst, for example
a fixed or fluid catalyst bed, packed with a suitable dehydrohalogenation
catalyst, with suitable means to heat the reaction mixture to about the
desired reaction temperature. The reaction vessel may employ single or
multiple tubes packed with a dehydrohalogenation catalyst.

[0051] The compound of Formula (IB), preferably HCFC-244bb, may be
introduced into the reactor either in pure form, partially purified form,
or as portion or entirety of the reactor effluent from the preceding
step. The compound of Formula (IB), such as HCFC-244bb, may optionally be
fed with an inert gas diluent such as nitrogen, argon, or the like. In a
preferred embodiment of the invention, the compound of Formula (IB), such
as HCFC-244bb, is pre-vaporized or preheated prior to entering the
reactor. Alternately, the compound of Formula (IB), such as HCFC-244bb,
may be vaporized in whole or in part inside the reactor.

[0052] While it is contemplated that a wide variety of reaction
temperatures may be used, depending on relevant factors such as the
catalyst being used and the most desired reaction product, it is
generally preferred that the reaction temperature for the
dehydrohalogenation step is from about 100° C. to about
800° C., more preferably from about 150° C. to about
600° C., and even more preferably from about 200° C. to
about 550° C.

[0053] In general it is also contemplated that a wide variety of reaction
pressures may be used, depending again on relevant factors such as the
specific catalyst being used and the most desired reaction product. The
reaction pressure can be, for example, superatmospheric, atmospheric or
under vacuum. The vacuum pressure can be from about 5 torr (0.0966 psig)
to about 760 torr (14.69 psig).

[0054] In certain embodiments, an inert diluent gas, such as nitrogen, may
be used in combination with the other reactor feed(s). When such a
diluent is used, it is generally preferred that the compound of Formula
(I), preferably Formula (IB), comprise from about 50% to greater than 99%
by weight based on the combined weight of diluent and Formula (I)
compound.

[0055] It is contemplated that the amount of catalyst use will vary
depending on the particular parameters present in each embodiment.
Contact time of the compound of Formula (IB), such as HCFC-244bb, with
the catalyst in certain preferred embodiments ranges from about 0.5
seconds to about 120 seconds, however, longer or shorter times can be
used.

[0056] Preferably in such dehydrofluorination embodiments as described in
this section, the conversion of the Formula (IB) compound is at least
about 10%, more preferably at least about 20%, and even more preferably
at least about 30%. Preferably in such embodiments, the selectivity to
compound of Formula (II), preferably HFO-1234yf, is at least about 70%,
more preferably at least about 85% and more preferably at least about
95%.

[0057] In certain preferred embodiments, the process flow is in the down
or up direction through a bed of the catalyst. It may also be
advantageous to periodically regenerate the catalyst after prolonged use
while in place in the reactor. Regeneration of the catalyst may be
accomplished by any means known in the art, for example, by passing air
or air diluted with nitrogen over the catalyst at temperatures of from
about 100° C. to about 400° C., preferably from about
200° C. to about 375° C., for from about 0.5 hour to about
3 days.

[0058] In general, the effluent from the dehydrohalogenation reaction
step, including any intermediate effluents that may be present in
multi-stage reactor arrangements, may be processed to achieve desired
degrees of separation and/or other processing. For example, in
embodiments in which the reactor effluent comprises a compound of Formula
II, such as HFO-1234yf, the effluent will generally also include HCl and
unreacted compound of the Formula (IB). Some portion or substantially all
of these components of the reaction product may be recovered from the
reaction mixture via any separation or purification method known in the
art such as neutralization and distillation. It is expected that
unreacted compound of the Formula (IB) could be recycled, completely or
partially, to improve the overall yield of the desired
CF3CF═CH2 (HFO-1234yf). Optionally but preferably, hydrogen
chloride is then recovered from the result of the dehydrochlorination
reaction. Recovering of hydrogen chloride is preferably conducted by
conventional distillation where it is removed from the distillate.

[0059] Alternatively, HCl can be recovered or removed by using water or
caustic scrubbers. When a water extractor is used HCl is removed as an
aqueous solution. When caustic is used, HCl is just removed from system
as a chloride salt in aqueous solution.

[0060] In an alternate embodiment of the invention, dehydrohalogenation of
HCFC-244bb can also be accomplished by reacting it with a strong caustic
solution that includes, but is not limited to KOH, NaOH, Ca(OH)2 and
CaO at an elevated temperature. In this case, the strength of the caustic
solution is preferably from about 2 wt % to about 100 wt %, more
preferably from about 5 wt % to about 90 wt % and most preferably from
about 10 wt % to about 80 wt %. The caustic:Formula (IB) mole ration,
preferably the caustic:HCFC-244bb mole ratio, preferably ranges from
about 1:1 to about 2:1; more preferably from about 1.1:1 to about 1.5:1
and even more preferably from about 1.2:1 to about 1.4:1. The reaction
may be conducted at a temperature of from about 20° C. to about
100° C., more preferably from about 30° C. to about
90° C. and even more preferably from about 40° C. to about
80° C. As above, the reaction may be conducted at atmospheric
pressure, super-atmospheric pressure or under vacuum. The vacuum pressure
can be from about 5 torr (0.0966 psig) to about 760 ton (14.69 psig). In
addition, a solvent or phase transfer catalyst such as Aliquat 336 may
optionally be used to help dissolve the organic compounds in the caustic
solution. This optional step may be conducted using solvents that are
well known in the art for said purpose. Thereafter, the Formula (II)
compound, preferably HFO-1234yf, may be recovered from the reaction
product mixture comprised of unreacted starting materials and by-products
by any means known in the art, such as by extraction and preferably
distillation. In certain preferred embodiments, the mixture of HFO-1234yf
and any by-products are passed through a distillation column. For
example, the distillation may be preferably conducted in a standard
distillation column at atmospheric pressure, super-atmospheric pressure
or a vacuum. Preferably the pressure is less than about 300 psig,
preferably less than about 150 psig and most preferably less than 100
psig. The pressure of the distillation column inherently determines the
distillation operating temperature.

[0061] Preferably in such dehydrofluorination embodiments as described in
this section, the conversion of the Formula (IB) compound is at least
about 60%, more preferably at least about 75%, and even more preferably
at least about 90%. Preferably in such embodiments, the selectivity to
compound of Formula (II), preferably HFO-1234yf, is at least about 70%,
more preferably at least about 85% and more preferably at least about
95%.

EXAMPLES

[0062] Additional features of the present invention are provided in the
following examples, which should not be construed as limiting the claims
in any way.

[0063] A 1.5'' 1D×24'' long PFA-lined pipe was filled with 550 grams
of antimony pentachloride liquid phase fluorination catalyst. This was
heated to approximately 95° C., and then fluorinated with 5 moles
of anhydrous hydrogen fluoride. Then a continuous feed of
1,1,2,3-tetrachloropropene was begun, simultaneous with continuous feed
of HF. These feeds were maintained in a mole ratio of HF to 1,1,2,3-TCP
of about 17:1, with a residence time of about 1 second. The reactor was
maintained at about 96° C. Volatiles from the run were collected
in a dry ice cold trap, analyzed, and found to produce a nearly total
conversion of the 1,1,2,3-tetrachloropropene, with selectivity of about
22% to 2-chloro-1,1,1,2-tetrafluoropropane (244bb), and selectivity of
about 33% to 2-chloro-3,3,3-trifluoropropene (1233xf), and selectivity of
about 27% to precursor 2,3-dichloro-3,3-difluoropropene (1232xf) and
selectivity of >12% to overchlorinated species 1223xd attributed to
excess Cl2 feed to the reactor to keep the catalyst active.

[0064] Example 1 was repeated except 515 grams of antimony pentachloride
was used, mole ratio of HF to 1,1,2,3-TCP is about 30:1, and the
residence time was about 2.1 seconds, and the pressure in the reactor was
allowed to build to about 14 psig. Volatiles from the run were collected
in a dry ice cold trap, analyzed, and found to produce a nearly total
conversion of the 1,1,2,3-tetrachloropropene, with selectivity of about
16.7% to 2-chloro-1,1,1,2-tetrafluoropropane (244bb), and selectivity of
about 33.5% to precursor 2-chloro-3,3,3-trifluoropropene (1233xf), and
selectivity of about 34.6% to precursor 2,3-dichloro-3,3-difluoropropene
(1232), and selectivity of >10.0% to overchlorinated species 1223xd
attributed to excess Cl2 feed to the reactor to keep the catalyst
active.

[0065] To a 1 Liter monel Parr reactor is added 83 grams of SbCl5 and
300 grams of HF. After heating to 85° C., the HCl and
noncondensibles are vented to a DIT. Then 50 grams of
CCl2═CClCH2Cl are quickly added. The mole % ratio of
SbCl5 to CCl2═CClCH2Cl is 50/50. There is an immediate
exotherm and the temperature rises to 97° C. almost
instantaneously. The variac controlling the heater is turned off and the
reaction held between 97 and 87° C. for an hour. The pressure
rises to 400 psig and levels off. A vapor sample is taken into gas bags
containing DI H2O (to absorb the HF and HCl prior to analysis). A GC
of the gas bag sample shows 53.5 GC area % 244bb, 1.46 GC area %
overfluorinated species HFC245cb, 6.6 GC area % overchlorinated species
1223xd along with 1233xf precursor, 1232xf precursor, and some C6
compounds that may be dimers. The conversion of
CCl2═CClCH2Cl on a GC area % basis is 100%.

Example 4

Conversion of CF3CFClCH3 (HCFC-244bb) to CF3CF═CH2
in Continuous Gas-Phase

[0067] Conversion of HCFC-244bb into HFO-1234yf was performed using Monel
reactor (ID 2 inch, length 32 inch) equipped with a Monel preheater (ID 1
inch, length 32 inch) which was filled with Nickel mesh to enhance heat
transfer. The reactor is filled with 2.0 L of pelletized 10 wt % CsC1/90
wt % MgF2 dehydrochlorination catalyst. Nickel mesh is placed at the
top and at the bottom of reactor to support the catalyst. Multi-point
thermocouple is inserted at the center of the reactor. The catalyst is
pretreated in dry N2 flow for 6 hours at the temperature of 480°
C. Then the feed with the composition 95 GC % 244bb/3.1 GC % 1233xf/0.35
GC % 245cb is introduced into the reactor at the rate of 1.0 lb/hr. The
feed is vaporized prior entering the reactor preheater. The bottoms of
the distillation column is discharged and recycled into the reactor. The
feed rate is maintained constant at 1.0 lbs/hr and both temperature and
pressure are varied. Temperature gradient throughout the reactor is
within about 3-5° C. The productivity of the catalyst is estimated
at 3-6 lbs/hr/ft3. The highest productivity is observed at
470° C. and 45 psig, and the lowest productivity is observed at
480° C. and 3 psig pressure. The reaction products are fed into
the caustic scrubber to remove HCl by-product. Then the product stream is
passed through a column filled with desiccant to remove residual
moisture. Oil-less compressor was used to feed crude product into the
distillation column that was maintained at 30-45 psig pressure.
Distillation was performed in a continuous mode and the take-off rate was
equal to the rate of production of HFO-1234yf in the reactor. The purity
of distilled 1234yf is 99.9 GC %+. GC analysis of the distillate shows
presence of light impurities with a ppm level of heavy impurities.